- Core Web Vitals are a direct Google ranking factor.
- LCP (Largest Contentful Paint) should be under 2.5 seconds.
- INP (Interaction to Next Paint) has replaced FID as the primary interactivity metric.
- Server response time (TTFB) is the foundation of good Core Web Vitals.
What Are Core Web Vitals?
Core Web Vitals are a set of specific metrics that Google considers important for a webpage's overall user experience. They measure loading performance, interactivity, and visual stability.
Direct Ranking Factor
Since June 2021, these metrics have been a direct ranking factor in Google Search. Sites that meet the recommended thresholds have a measurable advantage in search results.
Largest Contentful Paint (LCP)
Google recommends an LCP of 2.5 seconds or less for a "Good" rating.
For WordPress sites, LCP is heavily influenced by server response time, render-blocking resources, and image optimisation. A slow hosting environment or unoptimised images can push LCP well beyond acceptable thresholds.
Interaction to Next Paint (INP)
Google has transitioned to INP (Interaction to Next Paint) as a more comprehensive interactivity metric, replacing the older FID metric.
JavaScript is the Enemy of INP
Heavy JavaScript execution is the primary cause of poor INP scores. WordPress sites loaded with plugins often have significant JavaScript overhead that blocks the main thread.
About Tom Bradley
Tom is a performance engineer with over a decade of experience optimizing high-traffic WordPress sites. He specializes in edge computing, caching architectures, and Core Web Vitals optimization.
